XPS M1530 Screen Black Out

The laptop is 22 months old and last week the screen suddenly started to just go black. The base hardware is CORE 2 DUO T5550 1.83Ghz running Vista Home Premium (fully updated). The display is a 15.4" WXGA (1280X800) with true life.

The video output is still there (just) but, the screen has practically gone black. The display will last anywhere between 30 to 120 seconds, I've timed it.

I've updated the BIOS to now run A12. I've restored to factory / delivery state using the Dell Recovery option, and reapplied all updates. I've checked the BIOS to see if there is some sort of power management setting and I've disabled this feature in Windows. Still the same result.

When I attached an external monitor the video output transfers across without a problem and the output remains. I can 're-activate' the laptop screen by trransferring the output back using Fn + F8. However, no matter what the scenario - single display or dual - randonly somewhere between 30 & 120 seconds the laptop display simply vanished.

The only thing I haven't done just yet is to open up the box and check that all of the wires are seated correctly.

As a last resort I could call out a Dell Tech, but I just wondered if anyone else out there had experienced something similar?

I have a inspiron about the same age as your lap top. The exact same problem just started. Black screen. If you shine a bright light onto the display I'll bet you see that everything is up and ruinning. When I close the lid and put it into hibernation and then reopen it the display works for about a minute and then goes black again.